Something that's always bugged me about Special Relativity?

Question

I've recently been brushing up on both General and Special Relativity, in hopes that it may help me with a Science Fiction story I'm writing (just an amateur past-time, so don't ever expect this to appear on the shelf at Borders).

Anyway, although I get the concept of the speed of light (c) being constant in all inertial reference frames, and the flow of time changes to account for this, I still don't understand how red and blue shift can occur.

Anyone have a reasonably straight forward answer, or is this something that would require an entire Thesis to explain?

Answer 1

Einstien's "relativity" book, which was written for everyday people, really does a wonderful job at explaining his theories... red shift and blue shift are a part of the doppler effect. So if you are standing in one place and listen to a loud noise pass by the noise will have a different pitch depending on where it is in relation to you.

I don't think this has anything to do with frequency, but more so pitch... and I don't think that a difference in pitch affects frequency. not sure though...

Answer 2

I believe its due to the doppler effect. when objects moving away the observed wavelength increases, reducing frequency and resulting in Red shift. the opposite causes blue shift. although there is a change in energy the speed of light is still the same in all inertial frames of reference as the energy of a photon has no bearing on its velocity.

Hope this helps a little

yes the oserved wavelength changes and so does the observed frequency. these two are inversly proportional to each other so one will alway affect the other. the important word here is the observed. If earth was travelling in the same velocity (speed and direction) our inertial frames would be the same and therefore there would be no red or blue shift.